Lack of Phosphorus May Hinder Development of Extraterrestrial Life

Credit: J. Greaves

The team used the UK’s William Herschel Telescope, sited on La Palma in the Canary islands, to observe infrared light from phosphorus and iron in the Crab Nebula, a supernova remnant around 6500 light years away in the direction of the constellation of Taurus.

Cigan, an expert on these stellar remnants, says: “This is only the second such study of phosphorus that has been made. The first looked at the Cassiopeia A (Cas A) supernova remnant, and so we are able to compare two different stellar explosions and see if they ejected different proportions of phosphorus and iron. The first element supports life, while the second is a major part of our planet’s core”.

The astronomers struggled with foggy nights at the telescope, back in November 2017, and are only just starting to get scientific results from a few hours of data.

Cigan cautions “These are our preliminary results, which we extracted only in the last couple of weeks! But at least for the parts of the Crab Nebula we were able to observe so far, there seems to be much less phosphorus than in Cas A. The two explosions seem to differ from each other, perhaps because Cas A results from the explosion of a rare super-massive star. We’ve just asked for more telescope time to go back and check, in case we’ve missed some phosphorus-rich regions in the Crab Nebula.”

This is a 15cm wide fragment of the Seymchan iron-nickel meteorite found in Russia in 1967. The long filament of dark grey material in the centre is the phosphorus-rich mineral schreibersite.

Credit: M. Pasek / University of South Florida.

The preliminary results suggest that material blown out into space could vary dramatically in chemical composition. Greaves remarks: “The route to carrying phosphorus into new-born planets looks rather precarious. We already think that only a few phosphorus-bearing minerals that came to the Earth – probably in meteorites – were reactive enough to get involved in making proto-biomolecules.

‘If phosphorus is sourced from supernovae, and then travels across space in meteoritic rocks, I’m wondering if a young planet could find itself lacking in reactive phosphorus because of where it was born? That is, it started off near the wrong kind of supernova? In that case, life might really struggle to get started out of phosphorus-poor chemistry, on another world otherwise similar to our own.”

Credit: IAC

The researchers now plan to continue their search, to establish whether other supernova remnants also lack phosphorus, and whether this element, so important for complex life, is rarer than we thought.

Contacts and sources:
Dr Robert Massey
Royal Astronomical Society